Microinjection of Murine ES cells? References or experiences

Hello All,
I am thinking of trying microinjection of mouse ES cells and I was
wondering what is involved as far as equipement (including rough
pricing??) and time. I have seen papers where they inject several
thousand cells (many a paper by Capecchi) and I was wondering how
difficult this is to do. We routinely inject pronuclei in mouse
oocytes. Is it much more involved than this?
Any and all hints, suggestions are appreciated
G. Dellaire
McGill dept of Medicine
Div. of Experimental Medicine.
dellaire at odyssee.net